The union representing Boeing’s engineers and technical workers delivered a split decision on the company’s contract offer Tuesday, with its engineers accepting the proposal but its technical professionals rejecting the offer and giving their OK for a future strike.

The 23,000 members of the Society for Professional Engineering Employees in Aerospace (SPEEA), who are mostly local, voted in two groups.

The larger group of engineers voted to accept Boeing’s offer, going against their leadership’s recommendation to turn down the proposed four-year contract.

The smaller group, consisting of technical professionals, narrowly turned it down and authorized a future strike.

The split vote is “a disappointment,” said SPEEA President Tom McCarty. But the negotiating team now has the authority to call a strike of the techs, he said.

The split vote is “a disappointment,” said SPEEA President Tom McCarty. But the negotiating team now has the authority to call a strike of the techs, he said.

Engineers approved the contract with a 54 percent vote. Tech workers voted 52.6 percent against the contract, and separately voted 64 percent to permit their leaders to call a strike.

SPEEA Executive Director Ray Goforth, who had vocally urged both groups to spurn Boeing’s proposal, called the divided vote an “interesting result.”

He said the union will ask Boeing to resume negotiations on a contract that the technical employees would find acceptable.

Meanwhile, he said, members should “bask in the accomplishment here.”

Boeing said it was pleased with the engineers’ vote but “deeply disappointed” that SPEEA’s technical workers turned down its offer.

Darry Kurpisz, a 23-year employee who represents techs, said his worst fear came true.

“This vote practically split the union,” he said. “Without the support of both bargaining units we don’t have as much leverage as before.”

But a union spokesman downplayed those fears, saying the engineers would support their fellow union members in spirit — but not with a strike.

The vote came at a critical juncture for he world’s leading airplane manufacturer. It is ramping up production to keep pace with orders and has hired thousands of new employees.

Meanwhile, Boeing has said the grounding of its new 787 jets a month ago requires mobilizing “hundreds of engineering and technical experts who are working around the clock” to solve problems with the plane’s lithium-ion batteries.

Boeing’s offer provided for 5 percent average annual salary increases for both engineers and technical professionals for four years; no new increases in employee health-care contributions; and an increase in the basic pension benefit.

The offer meant that over four years, the average engineer would see $84,071 in additional salary and incentive pay under Boeing’s proposed contract, while the average technical employee would get an added $64,515.

Newly hired engineers earn less than $70,000 a year, while veteran engineers can earn more than $200,000. The average Boeing engineer’s salary is $110,000.

The two sides began talks in April. Existing contracts for the roughly 15,550 engineers and 7,400 technical workers represented by the union expired Nov. 25.

Boeing then made some improvements to the pool of annual salary increases for both engineers and technical employees.

But last month, the union’s negotiating committee rejected the offer, focusing on a provision that would replace the pension benefit for new employees with a 401(k)-retirement plan SPEEA says would pay 40 percent less income during retirement. Boeing differs with the union on the estimated financial impact, but says it must reduce the cost of pension benefits to remain competitive.

“It’s time for the company to stop wasting resources and improve its offer to reflect the value and contributions technical workers bring to Boeing,” said SPEEA’s Goforth in a statement. “That way, we can avoid a strike and focus on fixing the problems of the 787 and restoring customer confidence in Boeing.”